I choose finaly to communication with HomeAssistant via the MQTT integration. 

MQTT is extremely light and reliable  for this purpose.

I'll add also a custom thermostat-card. I'll show you this late...

Here me MQTT communication protocol : 

I also add a frequently a STATE information in JSON format 

device_7/STATE :
{"power":"OFF","op_mode":"off","swing_mode":"off","fan_speed":"auto","temperature":21,"room_temp":22,"RSSI":-55}

and a MQTT last will message to be able to check if the device is on or offline.

device_7/LWT :
Online